The article describes the knowledge, attitudes and practices of birth defect prevention (BD) of 400 pregnant women in Cam Xuyen district, Ha Tinh province and analyzes some factors related to prevention practices. The study used a cross-sectional descriptive research method. Research results show that 74.3% of subjects have BD knowledge at the pass level; 94.5% have a positive attitude and 92% practice good BD. There is a relationship between the level of education, knowledge, and attitudes about BD with mothers' practice of preventing BD. The difference is statistically significant with OR and 95% CI, respectively: OR=2.673; 95% CI = (1.263 – 5.657); OR=16.377; 95% CI (6.510 – 41.198); OR = 3.824; 95%CI = (1.310 - 11.160). Conclusion: The knowledge, attitude and practice of BD prevention among pregnant women in Cam Xuyen district, Ha Tinh province is very good.